Down-the-hole drilling control system for mobile drilling machines

ABSTRACT

A method for automated control of a drilling operation of a blast hole drilling machine using a down-the-hole drill bit mounted on a drill string is disclosed. The method may include: receiving input data from a user input including information of the drill bit, drill string weight, and desired hole settings; receiving a command from the user to initiate an automatic down-the-hole operation; identifying a location of the down-the-hole drill bit; and using the received input data and based on the location of the down-the-hole drill bit, automatically initiating the steps of: collaring a hole; drilling the hole; and retracting the drill when the hole is drilled.

TECHNICAL FIELD

The present disclosure relates generally to mobile drilling machines, and more particularly, to a down-the-hole control system for such machines.

BACKGROUND

Mobile drilling machines, such as blasthole drilling machines, are typically used for drilling blastholes for mining, quarrying, dam construction, and road construction, among other uses. The process of excavating rock, or other material, by blasthole drilling comprises using the blasthole drill machine to drill a plurality of holes into the rock and filling the holes with explosives. The explosives are detonated causing the rock to collapse and rubble of the collapse is then removed and the new surface that is formed is reinforced. Many current blasthole drilling machines utilize rotary drill rigs, mounted on a mast, that can drill blastholes anywhere from 6 inches to 22 inches in diameter and depths up to 180 feet or more.

Blasthole drilling machines may also include a down-the-hole (DTH) drilling mode for drilling into hard rock. In the DTH drilling mode, a hammer-type drill bit may be mounted on the drill string for down-the-hole drilling. The hammer-type drill bit may utilize a percussion mechanism, such as a piston, controlled by air pressure to repeatedly strike the drill bit for “hammering” into the hole as the drill bit is fed into the hole. Down-the-hole drilling may further include applying a pulldown force from a hydraulic feed cylinder to a rotary head for controlling a feed rate of the drill bit (attached to a drill string mounted on the rotary head) into the ground. As such, the hammer-type drill bit may exert an axial force on a bottom surface of the hole as the drill bit moves down for creating the hole. An opposite axial force, or compressional load force, is exerted on the drill bit (and thus the drill string) by the bottom surface of the hole. During the down-the-hole drilling operation, it is desirable to maintain the compressional load force on the drill bit in a target range while the drill bit moves down the hole. For example, the drill bit or drill string may be damaged if too much compressional load force is exerted on the drill bit, and/or the forces may inhibit the hammering motion of the drill bit. As such, it may be necessary to adjust the feed of the drill bit such that the compressional load force is maintained in the target load force range during the drilling operation.

U.S. Pat. No. 7,198,117, issued to Uitto on Apr. 3, 2007 (“the '117 patent”), describes a rock drilling arrangement and a method for controlling rock drilling on the basis of specific energy. The '117 patent describes a control device to control a percussion device, a rotating device, and a feeding device of the rock drilling machine based on sensor data so that minimum specific energy is used during the drilling operation. The control device of the '117 patent may adjust drilling variables such as: percussion power, impact energy, impact frequency, feeding power, feeding rate, rotating rate, rotating torque, flushing flow, and flushing pressure to minimize specific energy. However, the '117 patent does not disclose automating the down-the-hole drilling process based on the sensor data.

The systems and methods of the present disclosure may address or solve one or more of the problems set forth above and/or other problems in the art. The scope of the current disclosure, however, is defined by the attached claims, and not by the ability to solve any specific problem.

SUMMARY

In one aspect, a method for automated control of a drilling operation of a blast hole drilling machine using a down-the-hole drill bit mounted on a drill string is disclosed. The method may include: receiving input data from a user input including information of the drill bit, drill string weight, and desired hole settings; receiving a command from the user to initiate an automatic down-the-hole operation; identifying a location of the down-the-hole drill bit; and using the received input data and based on the location of the down-the-hole drill bit, automatically initiating the steps of: collaring a hole; drilling the hole; and retracting the drill when the hole is drilled.

In another aspect, a method for automated control of a drilling operation of a blast hole drilling machine using a down-the-hole drill bit mounted on a drill string is disclosed. The method may include: automatically identifying a location of the down-the-hole drill bit; and based on the location of the down-the-hole drill bit, automatically collaring a hole or automatically drilling the hole.

In another aspect, a method for automated control of a collaring operation of a blast hole drilling machine using a down-the-hole drill bit mounted on a drill string is disclosed. The method may include: automatically supplying air to the down-the-hole drill bit to provide a hammering action at the drill bit without rotating the drill bit; and automatically feeding the down-the hole drill bit to form an initial hole.

In another aspect, a method for automated control of a drilling operation of a blast hole drilling machine using a down-the-hole drill bit mounted on a drill string is disclosed. The method may include: automatically supplying air to the down-the-hole drill bit to provide a hammering action at the drill bit; and automatically controlling a feed rate of the drill string based on a measured bit air pressure during the drilling operation.

In yet another aspect, a method for automated control of a drilling operation of a blast hole drilling machine using a down-the-hole drill bit mounted on a drill string is disclosed. The method may include: automatically supplying air to the down-the-hole drill bit to provide a hammering action at the drill bit; automatically controlling a feed rate of the drill string based on a measured bit air pressure during the drilling operation; and automatically initiating a jam avoidance operation when the bit air pressure is above a first value, but below a second value, or a measured rotation torque of the drill string is above a first torque value.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and together with the description, serve to explain the principles of the disclosure.

FIG. 1 illustrates a schematic side view of a drilling machine with an exemplary down-the-hole drilling control system, according to aspects of the disclosure.

FIG. 2 illustrates a schematic view of the exemplary down-the-hole drilling control system of the drilling machine of FIG. 1.

FIG. 3 illustrates a flowchart depicting an exemplary automatic down-the-hole (auto-DTH) drilling operation of the down-the-hole drilling control system if FIGS. 1 and 2.

FIG. 4 provides a flowchart depicting an exemplary bit location identification phase of the down-the-hole drilling control system of FIGS. 1-3.

FIG. 5 provides a flowchart depicting an exemplary collaring phase of the down-the-hole drilling control system of FIGS. 1-3.

FIG. 6 provides a flowchart depicting an exemplary hole drilling phase of the down-the-hole drilling control system of FIGS. 1-3.

FIG. 7 provides a flowchart depicting an exemplary drill retracting phase of the down-the-hole drilling control system of FIGS. 1-3.

DETAILED DESCRIPTION

Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the features, as claimed. As used herein, the terms “comprises,” “comprising,” “having,” including,” or other variations thereof, are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such a process, method, article, or apparatus. Further, relative terms, such as, for example, “about,” “substantially,” “generally,” and “approximately” are used to indicate a possible variation of ±10% in a stated value.

FIG. 1 illustrates a schematic side view of an exemplary drilling machine 10. The disclosure herein may be applicable to any type of drilling machine, however, reference will be made below particularly to a mobile blasthole drilling machine. As shown in FIG. 1, mobile drilling machine 10 may include a frame 12, machinery 14, and a drilling mast 16. Frame 12 may be supported on a ground surface by a transport mechanism, such as crawler tracks 18. Crawler tracks 18 may allow mobile drilling machine 10 to maneuver about the ground surface to a desired location for a drilling operation. Frame 12 may further include one or more jacks 20 for supporting and leveling mobile drilling machine 10 on the ground surface during the drilling operation. Frame 12 may support the machinery 14, which may include engines, motors, batteries, pumps, air compressors, a hydraulic fluid storage tank 36 (shown schematically in FIG. 1) and/or any other equipment necessary to power and operate mobile drilling machine 10. Frame 12 may further support an operator cab 22, from which a user, or operator, may maneuver and control mobile drilling machine 10 via a user interfaces and displays 40.

As further shown in FIG. 1, drilling mast 16 may include a mast frame 24 which may support a drill motor assembly, or rotary head 26, movably mounted on the mast frame 24. Rotary head 26 may couple to, and may be controllable to rotate, a drill string 28 of drilling pipe segments on which a down-the-hole hammer-type drill bit 30 may be mounted for down-the-hole drilling into the ground surface, as further described below. Rotary head 26 may be any type of rotary head, such as a hydraulic rotary head or the like. Rotary head 26 may further include a hydraulic fluid line (not shown) for receiving hydraulic fluid. The hydraulic fluid may be used to rotate a shaft of rotary head 26 on which the drill string 28 is connected for rotating the drill string 28 (and thus rotating drill bit 30). The hydraulic fluid line of rotary head 26 may be coupled to a hydraulic valve 32 (shown schematically in FIG. 1) for controlling the amount, and flow rate, of the hydraulic fluid into rotary head 26. In the exemplary embodiment, hydraulic valve 32 may be located on the hydraulic fluid storage tank 38. However, hydraulic valve 32 may be located anywhere along the hydraulic fluid line of the rotary head 26, as necessary.

Drilling mast 16 may further include a hydraulic feed cylinder 34 (located within mast frame 24) connected to rotary head 26 via a cable and pulley system (not shown) for moving rotary head 26 up and down along the mast frame 24. As such, when hydraulic feed cylinder 34 is extended, hydraulic feed cylinder 34 may exert a force on rotary head 26 for pulling-down rotary head 26 along mast frame 24. Likewise, when hydraulic feed cylinder 34 is retracted, hydraulic feed cylinder 34 may exert a force on rotary head 26 for hoisting up rotary head 26 along mast frame 24. Thus, hydraulic feed cylinder 34 may be controllable to control rotary head 26 to move up and down the mast frame 24 such that drill bit 30 on drill string 28 may be pulled-down towards, and into, the ground surface or hoisted up from the ground surface. As used herein, the term “feed” in the context of the feed cylinder 34 includes movement of the drill string 28 in either direction (up or down). Hydraulic feed cylinder 34 may include hydraulic fluid lines (not shown) for receiving and conveying hydraulic fluid to and from the feed cylinder 34. The hydraulic fluid may be used to actuate hydraulic cylinder 34 such that a rod of hydraulic cylinder 34 may be extended or retracted. The hydraulic fluid line of hydraulic cylinder 34 may be coupled to hydraulic valves 36 (shown schematically in FIG. 1) for controlling the amount, and flow rate and pressure, of the hydraulic fluid into hydraulic cylinder 34. In the exemplary embodiment, hydraulic valve 36 may be located on the hydraulic fluid storage tank 38. However, hydraulic valve 36 may be located anywhere along the hydraulic fluid line of the hydraulic cylinder 34, as necessary. It is understood that hydraulic fluid may be any type of hydraulic fluid, such as hydraulic oil or the like.

FIG. 1 shows the drill string 28 located in hole 50. The hole 50 includes a collaring portion 52 at a top portion of the hole, and a bottom of the hole 54 (e.g., desired depth of hole). As shown by the arrows in FIG. 1, drill string 28 can rotate, and move up and down (e.g. feed and retract/hoist) such that drill bit 30 rotates and moves up and down, respectively. Further drill string 28 may include water and air lines (not shown) for supplying water and/or compressed air through the drill bit 30 to the hole 50.

FIG. 2 illustrates a schematic view of the exemplary down-the-hole drilling control system of the drilling machine of FIG. 1. Control system 200 may include inputs 212-228, controller 210, and outputs 230-240. The inputs may include sensor input, operator inputs, or stored inputs, for example, bit information 212, drill string weight 214, desired hole settings 216, feed rate limits, rotation speed limits, air pressure limits and torque limits, bit air pressure 218, pulldown force 220, rotation torque 222, bit position 224, rotation speed 226, and signals from one or more inertial measurement units 228. Such sensors, operation input, or stored inputs may be obtained using any conventional system (sensors, user inputs, etc.) Outputs 106 may include, for example, a feed rate command 230, air supply command 232, drill string rotation command 236, watering command 238, and display information 240 for the operator.

Controller 210 may embody a single microprocessor or multiple microprocessors that may include means for monitoring operation of the drilling machine 10 and issuing instructions to components of machine 10. For example, controller 210 may include a memory, a secondary storage device, a processor, such as a central processing unit or any other means for accomplishing a task consistent with the present disclosure. The memory or secondary storage device associated with controller 210 may store data and/or software routines that may assist controller 210 in performing its functions. Further, the memory or secondary storage device associated with controller 210 may also store data received from the various inputs 102 associated with mobile drilling machine 10. Numerous commercially available microprocessors can be configured to perform the functions of controller 210. It should be appreciated that controller 210 could readily embody a general machine controller capable of controlling numerous other machine functions. Various other known circuits may be associated with controller 210, including signal-conditioning circuitry, communication circuitry, hydraulic or other actuation circuitry, and other appropriate circuitry.

Bit information input 212 may include a user input of bit type and a weight on the bit per diameter. Bit type may include a down-the-hole bit. However, bit type may also include any other type of drill bit, such as rotary drill bit, claw drill bit, or the like. The weight on the bit per diameter may be determined by a user input of the diameter of the bit. The user input may be received from an input device 40, such as a computing device, number pad, or the like.

Drill string weight input 214 may include a total weight of the drill string 28. The total weight of the drill string may be determined by a weight of the rotary head assembly 26, a weight of the drill pipes currently on the drill string 28, and a weight of the drill bit assembly. The weight of the rotary head assembly may be input by a user or may be pre-loaded and stored in the memory of controller 210. The weight of the drill pipes currently on the drill string may be determined based on a user input of the number of pipes currently on the drill string. To determine the weight of the drill pipes currently on the drill string, controller 210 may calculate the input number of pipes multiplied with the weight of a single pipe. The weight of the drill bit assembly may be determined by a user input or may be pre-loaded in the memory of controller 210.

Desired hole settings input 216 may include user input of, for example, a desired collar depth, reaming increments, and desired hole depth. Desired collar depth may be the desired depth in which the front end, or collar, of the hole 50 is drilled. Reaming increments may be depth increments by which the hole may collared during the auto-DTH drilling operation. Desired hole depth may be the desired depth in which the hole 50 is drilled during the auto-DTH drilling operation.

Feed rate limits input, rotation speed limits input, air pressure limits input, and torque limits input may be stored in the memory of controller 210. Feed rate limits may include maximum limits for the feed rate of the drill bit 30. Rotation speed limits may include maximum limits for the rotation speed of the drill bit 30. Air pressure limits may include maximum limits for an amount of air pressure provided for the piston of the hammer-type drill bit 30. Torque limits may include maximum limits for torque speed of the drill bit 30.

Bit air pressure input 218 may be a sensor for detecting and/or communicating a net force acting on an air supply line. Forces acting on the air supply line may include air pressure. Bit air pressure input 218 may be an air pressure sensor configured to communicate an air pressure signal indicative of air pressure of the air supply line on the drill bit 30 to controller 210. For example, an air pressure sensor may be located in the air supply line adjacent the drill bit 30 so as to detect pressure of fluid (e.g., air) within the air supply line. Bit air pressure input 218 may also derive air pressure information from other sources, including other sensors.

Pulldown force input 220 may be a sensor or other mechanism configured to detect and/or communicate a pulldown force acting on the drill bit 30. The pulldown force acting on the drill bit 30 may be the force exerted by the hydraulic feed cylinder 34 through the rotary head 26 to the drill bit 30. As such, the pulldown force may be derived from a pressure of the hydraulic feed cylinder. Thus, pulldown force input 220 may be a sensor for detecting a net force acting on the hydraulic feed cylinder 34, which may be controlled by controller 210. Forces acting on the hydraulic feed cylinder 34 may include a head end pressure and a rod end pressure. Rod end pressure may be low so that a net force acting on the hydraulic feed cylinder 34 may be approximated as a head-end pressure. For example, pulldown force input 220 may be a pressure sensor configured to communicate a pressure signal to controller 210. The pressure sensor may be disposed within a head of hydraulic feed cylinder 34. Alternatively, any sensor associated with pulldown force input 220 may be disposed in other locations relative to the hydraulic feed cylinder 34. Pulldown force input 220 may also derive pulldown force information from other sources, including other sensors.

Rotation torque input 222 may be a sensor or other mechanism configured to detect and/or communicate a rotation torque of the drill bit 30. A torque sensor may be physically associated with the drill bit 30 or may be a virtual sensor used to calculate a rotation torque based on sensed parameters such as rotation speed of the rotary head 26 and pressure at the rotary head 26. As such, rotation torque input 222 may include a sensor (e.g., a speed sensor) for detecting rotation speed of the rotary head 26 (and thus the drill bit 30) and a sensor (e.g., a pressure sensor) for detecting pressure of a fluid supply to the rotary head 26. The speed sensor may be disposed on or near the rotary head 26 and the pressure sensor may be disposed within a fluid supply line of the rotary head 26. Alternatively, any sensor associated with rotation torque input 222 may be disposed in other locations relative to the rotary head 26 and/or drill bit 30. Rotation torque input 222 may also derive rotation torque information from other sources, including other sensors.

Bit position 224 input may be a sensor or other mechanism configured to detect and/or communicate a position of the drill bit 30. For example, a position sensor may be physically associated with the rotary head 26 for detecting the position of the drill bit 30. As such, the position sensor may send a bit position signal to controller 210. The bit position signal may be derived from a position of the rotary head 26 relative to a location on the drill mast 16. For example, the bit position relative to the ground surface and/or the hole may be derived from the position of the rotary head 26 on the drill mast 16. The position sensor may be disposed on or near the rotary head 26. Alternatively, any sensor associated with the bit position input 224 may be disposed in other locations relative to the rotary head 26 and/or drill bit 30. Bit position input 224 may also derive bit position information from other sources, including other sensors.

Rotation speed 226 input may be a sensor (e.g., a speed sensor) that may be configured to detect a rotation speed of the drill bit 30. Rotation speed input 226 may communicate a rotation speed signal indicative of a rotation speed of the drill bit 30 to controller 210. For example, rotation speed input 226 may monitor the rotation speed of the rotary head 26. Rotation speed input 226 may embody a conventional rotational speed detector having a stationary element rigidly connect to the rotary head 26 that is configured to sense a relative rotational movement of the rotary head 26 (e.g., of a rotational portion of the rotary head 26 that is operatively connected to the rotary head 26, such as a shaft of the rotary head 26 or the drill string 28 mounted on the rotary head 26). The stationary element may be a magnetic or optical element mounted to a housing of the rotary head assembly and configured to detect rotation of an indexing element (e.g., a toothed tone wheel, an embedded magnet, a calibration stripe, teeth of a timing gear, etc.) connected to rotate with the shaft of the rotary head 26. A sensor of rotation speed input 226 may be located adjacent the indexing element and configured to generate a signal each time the indexing element (or a portion thereof) passes near the stationary element. The signal may be directed to controller 210, which may use the signal to determine a number of shaft rotations of the rotary head 26, occurring within fixed time intervals, and use this information to determine the rotation speed value.

Inertial measurement unit (IMU) input 228 are sensors on drilling machine 10 components that can measure various aspects of movement of the component, such as accelerations in the x, y, z directions, and rates of change for pitch, roll, and yaw. Outputs from the IMUs may be use with values of the overall pitch and roll of the machine.

For outputs of control system 200, feed rate command 230 may cause actuation of the hydraulic feed cylinder 34 and may cause a change of position of rotary head 26 up and down along the mast frame 24. As such, feed rate command 230 may control the feed rate of drill bit 30 into and out of the hole 50. Air supply command 232 may cause actuation of a valve in the air supply line of the rotary head 26. As such, air supply command 26 may control air pressure exerted on the drill bit 30. Drill string rotation command 236 may cause actuation of the valve of hydraulic fluid line of the rotary head 26. As such, drill string rotation command 236 may control the rotation speed of the drill string 28 (and thus the drill bit 30). Watering command 238 may cause actuation of a valve of the watering line. As such, the watering command 238 may control water pressure and amount of water of the watering line. Display outputs 240 can take many different forms to inform the operator or remote personnel of the status of various aspects of the auto-DTH drilling process 300.

FIG. 3 provides the various phases of an auto-DTH drilling operation 300. In particular, the auto-DTH drilling operation 300 includes an initial input DTH data phase 310, an initiate auto-DTH phase 312, an identify location of bit phase 314, a collar hole phase 316, a drill hole phase 318, a retract drill phase 320, and a deactivate auto-DTH phase 322. In the input DTH data phase 310, the operator of drilling machine 10 or remote personnel may provide various data required for the auto-DTH drilling operation 300. Such data may include, for example, bit information 212 (e.g. bit type, load limits of bit, size of bit, etc.), drill string weight 214 (e.g. weight of pipe and number of pipes on the drill string 28), and desired hole settings 216 (e.g. collaring depth, reaming increment depth, and desired depth of hole).

In the initiate auto-DTH phase 312, the operator of drilling machine 10 may initiate the auto-DTH drilling operation 300 via a button or other software interface in the operator cab 22. The button or other software interface may be located anywhere in the operator cab, for example, on a control joystick 40, a touch screen interface, or any other device for providing control signals to controller 210. Alternatively, or additionally, the initiate auto-DTH phase 312 may include remote personnel initiating the auto-DTH drilling operation 300 via remote triggering by a remote device.

In the identify location of bit phase 314, controller 210 may receive signals indicating a current location of drill bit 30. Based on the location of drill bit 30, controller 210 may automatically initiate or resume the collar hole phase 316, initiate or resume the drill hole phase 310, and/or initiate or resume a retract drill phase 320. In the collar hole phase 316, controller 210 may automatically collar a hole based on the input desired hole settings 216, such as the collaring depth (e.g., 3 meters) and the reaming increment depth (e.g., half meter increments). After the collar hole phase 316, controller 210 may automatically initiate the drill hole phase 318. In the drill hole phase 318, controller 210 may automatically drill the hole based on the input desired hole settings 216, such as desired depth of hole. For example, drill bit 30 may be lowered to the ground for drilling (e.g., by a feed down command) and drilling may be continued until the desired hole depth has been reached. When the desired hole depth is reached, controller 210 may automatically initiate the retract drill phase 320. In the retract drill phase 320, controller 210 may automatically stop the feed down command such that drilling of the hole is stopped and controller 210 may automatically retract drill bit 30 out of the hole. When drill bit 30 is out of the hole and raised to a level such that drilling machine 10 may tram and/or mast 16 may be lowered, the drilling cycle in the auto-DTH drilling operation 300 may be complete. When the auto-DTH drilling operation 300 is complete, controller 210 may deactivate the auto-DTH drilling operation 300 in the deactivate auto-DTH phase 322. The identify location of bit phase 314, collar hole phase 316, drill hole phase 318, retract drill phase 320, and deactivate auto-DTH phase 322 will be detailed further below.

FIG. 4 provides an exemplary identify location of bit phase 314 for the auto-DTH drilling operation 300. In the identify location of bit phase 314, controller 210 may receive signals indicating a current location of drill bit 30. Controller 210 may determine if drill bit 30 is above the ground and if the hole depth is zero (Step 410). If drill bit 30 is above the ground and the hole depth is zero, controller 210 may begin by feeding drill bit 30 toward the ground until the ground is detected (i.e., until drill bit 30 contacts the ground) (Step 412). The initial step (Step 412) of feeding drill bit 30 toward the ground may be triggered manually by the operator in the operator cab 22 or may be automatically initiated by controller 210. Once the ground has been detected (i.e., drill bit 30 contacts the ground), drill bit 30 may be hoisted, or retracted, slightly to initiate air supply to drill bit 30 for a hammering operation (Step 414). After the air supply is initiated, controller 210 may feed (i.e., lower) drill bit 30 to the ground to begin the collar hole phase 316 (Step 416) for collaring the hole, detailed further below.

The auto-DTH drilling operation 300 may also be initiated or resumed to resume the collar hole phase 316, drill hole phase 318, or retract drill phase 320. For example, if the auto-DTH drilling operation 300 is initiated and drill bit 30 is in the hole, the hole depth is not zero, and/or hole depth is less than the desired hole depth, controller 210 may feed drill bit 30 down the hole until the bottom surface of the hole is detected (i.e., until drill bit 20 contacts the bottom surface) (Step 418). Once the bottom surface of the hole has been detected, drill bit 30 may be hoisted, or retracted, slightly to initiate air supply to drill bit 30 for a hammering operation (Step 420). After the air supply is initiated, drill bit 20 may be lowered to the bottom surface of the hole to resume the collar hole phase 316 or the drill hole phase 318 (Step 422). For example, if the collar hole phase 316 has not been completed when the auto-DTH drilling operation 300 is initiated, controller 210 may resume collaring the hole or if the drill hole phase 318 has not been completed when the auto-DTH drilling operation 300 is initiated, controller 210 may resume drilling the hole. If the auto-DTH drilling operation 300 is initiated or resumed during the retract drill phase 320, controller 210 may resume retracting drill bit 30.

FIG. 5 provides an exemplary collar hole phase 316 for the auto-DTH drilling operation 300. The collar hole phase 316 may include initiating collaring without rotation of the drill string 28 (step 510). For example, collaring may be initiated by an air supply command 232 from controller 210 to supply air to the drill bit 30 to provide a hammering action at the drill bit 30 without rotating the drill bit 30. Controller 210 may then provide a feed command 230 to feed the drill bit 30 to the ground to form an initial hole. When the initial hole is formed and/or if the penetration rate is too low to form an initial hole, controller 210 may provide a drill string rotation command 236 to initiate rotation of drill string 28 at a rotation speed (step 512). Controller 210 may then continue to provide a feed command 230 to feed the drill bit 30 down the hole to drill a collar hole until a desired collaring depth (e.g., 3 meters) is achieved. In some embodiments, the collar hole phase 316 may include reaming increments (e.g., half meter increments). For example, controller 210 may provide a feed command 230 to feed the drill bit 30 to a predetermined collaring increment (e.g., half meter) and then retract the drill bit 30 (step 514). This process may be repeated until the desired collaring depth is achieved (step 516). When the desired collaring depth is achieved, controller 210 may retract the drill bit 30 from the bottom of the hole (step 518). The collar hole phase 316 may be discontinued when the desired collaring depth is met and the drill bit 30 is retracted (step 518) prior to feeding the drill for drilling (step 520) for the drill hole phase 318.

FIG. 6 provides an exemplary drill hole phase 318 for the auto-DTH drilling operation 300. The drill hole phase 318 takes place automatically after the collar hole phase 316, and in particular, after the retracting of the drill string 28 after collaring (step 518). The drill hole phase 318 may be discontinued when the desired hole depth has been achieved (step 624).

The drill hole phase 318 may include feeding the drill string 28 in the hole 50 at a feed rate (or feed velocity) while rotating the drill string 28 based on the feed velocity (step 610). The feed rate may be controlled by a feed command 230 from controller 210 to feed cylinder pump/control valves associated with the feed cylinder 34. The feed command 230 may initially correspond to a predetermined feed rate from controller 210. For example, this initial feed command could correspond to a max feed rate limit. However, this feed command 230 may be limited by a measured bit air pressure 218 corresponding to the air pressure in the drill string 28. In particular, the bit air pressure 218 may be monitored during the drill hole phase 318, and when the sensed bit air pressure 218 approaches a predetermined bit air pressure limit (step 612), the controller 210 may automatically adjust the feed command 230 to decrease the feed rate of the drill string 28 from the predetermined feed rate (max feed rate limit). The adjusted feed command 230 may be controlled to maintain a feed rate at or below the bit air pressure limit (step 614). The air pressure limit may correspond to a load on the drill bit 30 that is sufficient to do efficient drilling, while not too high to seize the drill bit 30 from reciprocating (hammering). This air pressure limit may be a single value or a range of values.

Rotation of the drill string 28 during the drill hole phase 318 may correspond to a drill string rotation command 236 that is based on the feed rate. For example, controller 210 may include a map, look-up table, or equivalent correlation process that associates a drill string rotation command 236 to the feed rate of the drill string 28. Further, the correlation between drill string rotation command 236 and feed rate may also be dependent upon the phase of the drilling process. In that, during different phases or sub-phases (e.g., jam avoidance and anti-jam), the relationship between feed rate and the drill string rotation command 236 may vary based on a numerical factor.

Under certain conditions, the measured bit air pressure 218 and/or the measured rotation torque 222 on the drill string 28 may increase beyond their respective limits during the drill hole phase 318. These conditions may represent a jam or impending jam of the drill string 28. The drill hole phase 318 may be configured to automatically react to these conditions. In particular, if the measured bit air pressure 218 and/or the measured rotation torque 222 is above a predetermined low limit, but below a predetermined high limit (step 616), the controller 210 may automatically initiate a “jam-avoidance” operation (step 618). The jam-avoidance operation may include sending a feed command 230 that reduces the feed rate of the drill string 28 based on the measured air pressure 218 and/or the measured rotation torque 222. By automatically reducing the feed rate of the drill string 28 in this manner, a jam of the drill string 28 may be avoided.

However, if the measured bit air pressure 218 and/or the measured rotation torque 222 increases above the predetermined high limit (step 620), the controller 210 may automatically initiate an “anti-jam” operation (step 622). The anti-jam operation may include sending a feed command 230 to move the drill string 28 in a hoist/retract direction or a feed direction to back away from the jam. Further, a drill string rotation command 236 may be sent to increase the drill string rotation speed to a high speed (a speed significantly higher than the speed prior to the anti jam operation, for example between 60-80% of a max rotation limit). Once the drill string 28 has reached the desired high speed condition, a feed command 230 may be provided to slowly feed the drill bit 30 into the jam. The slow feed rate can be significantly slower than the feed prior to the anti jam operation, for example between 5-20% of the feed rate limit). The direction of movement of the drill string 28 could be in either the feed direction or the hoist/retracting direction, depending on whether the jam is determined to be at the bottom of the hole or above the drill bit due to a caving in of the hole. This process of backing away from the jam and slowly reentering the jam can be automatically repeated until the jam is cleared (e.g. bit air pressure 218 and/or rotation torque 222 are lowered to acceptable levels).

The low limits and high limits for bit air pressure 218 and rotation torque 222 may be configurable—adjustable based on user inputs, or may be manufacturer set values and not configurable.

FIG. 7 describes the automatic retract drill phase 320 of the automatic DTH drilling operation 300, and begins when the desired drill depth is met (FIG. 6, step 624). When the drill depth is met, the feeding of the drill string 28 down the hole is discontinued and a “clear hole” operation may be activated (step 714). The “clear hole” operation may include the drill bit 30 being hoisted slightly above the bottom of the hole (step 712). For example, the drill bit 30 may be raised in the range of 50 to 150 mm above the bottom of the hole to protect the drill bit 30 from breaking. The drill bit 30 may stay at this depth for a predetermined time based on the depth of the hole, while air is being supplied through the drill string 28. For example, the drill bit 30 may maintain a position slightly above the bottom of the hole for 15 seconds for a 10 meter deep hole and blow air during this time, or for 30 second for a 20 meter deep hole. The continued air supply to the drill bit 30 serves to clear the hole of dirt and debris.

After the clear hole process is complete, the drill bit 30 may be retracted from the hole. During retraction, the drill bit 30 may be rotated at an idle rotation speed (step 716). Further, air may continue to be supplied through the drill string 28, but such air supply may be discontinued prior to reaching the collar portion of the hole. The drilling machine 10 may then detect when the drill bit 30 is out of the hole and at a position where the drill machine 10 may tram and/or the mast 16 could be lowered (step 718). At this point the retraction/hoisting of the drill bit 30 may be discontinued, along with the rotation of the drill string 28. A signal or other notification may then be provided to the machine operator and/or remote location that the auto-DTH drilling operation 300 is complete. The auto-DTH drilling operation 300 may then be automatically deactivated (step 720).

Under certain conditions, the measured bit air pressure 218 and/or the measured rotation torque 222 on the drill string 28 may increase beyond their respective limits during retraction/hoisting of the drill bit 30. These conditions may represent a jam of the drill string 28. The retract drill phase 320 may be configured to automatically react to these conditions. In particular, if the measured bit air pressure 218 and/or the measured rotation torque 222 increases above the predetermined high limit, the controller 210 may automatically initiate an “anti-jam” operation, as detailed with respect to FIG. 6 above.

To the extent that the operator halts the Auto-DTH process during the retract drill phase 320, (e.g. to assist in clearing a particularly problematic jam), resuming the Auto-DTH drilling operation will continue where the process was halted. For example, the drill bit 30 will not lower back down to the bottom of the hole.

INDUSTRIAL APPLICABILITY

The disclosed aspects of down-the-hole drilling control system 100 of the present disclosure may be used in any drilling machine having a down-the-hole drilling mode.

As used herein, the terms automated and automatic are used to describe functions that are done without user intervention. Thus, the auto-DTH drilling operation 300, as well as the various phases and functions of FIGS. 3-7, may all proceed without user intervention.

Such a down-the-hole drilling control system 100 may enable an automatic drilling operation. For example, the disclosed system 100 may allow an operator to input desired hole settings and trigger (either manually or automatically) the auto-DTH process. The disclosed system 100 may receive various sensor inputs, as described above, and control feed rate, drill string rotation, air supply, and watering supply functions to automatically drill a hole to the desired hole settings. Further, system 100 may help to ensure the compressional load force on the drill bit is maintained in the target load force range during the drilling operation. Such a system 100 may create a more intuitive operator control and may allow more autonomy of the drilling machine 10. Thus, the down-the-hole drilling control system 100 of the present disclosure may help operators execute the drilling operation and may help to reduce damage to the drill bit during the drilling operation, while decreasing overall drilling time.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed system without departing from the scope of the disclosure. Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims. 

1. A method for automated control of a drilling operation of a blast hole drilling machine using a down-the-hole drill bit mounted on a drill string, comprising: receiving input data from a user input including information of the drill bit, drill string weight, and desired hole settings; receiving a command from the user to initiate an automatic down-the-hole operation; identifying a location of the down-the-hole drill bit; and using the received input data and based on the location of the down-the-hole drill bit, automatically initiating the steps of: collaring a hole; drilling the hole; and retracting the drill when the hole is drilled. 2-3. (canceled)
 4. The method for automated control of claim 1, wherein the desired hole settings include collar depth, reaming increment depth, and a desired depth of the hole.
 5. The method for automated control of claim 4, further comprising if the down-the-hole drill bit is above ground and a depth of the hole is zero, automatically collaring the hole based on the collar depth and reaming increment depth.
 6. The method for automated control of claim 5, further comprising if the down-the-hole drill bit is in the hole or the hole depth is not zero, automatically drilling the hole based on the desired depth of the hole.
 7. The method for automated control of claim 6, wherein automatically drilling the hole includes a jam avoidance process of automatically reducing a feed rate of the down-the-hole drill bit to maintain an air pressure or torque on the down-the-hole drill bit within a target load limit range.
 8. The method for automated control of claim 6, wherein automatically drilling the hole includes an anti-jam process of automatically increasing a rotation speed and reducing a feed rate of the down-the-hole drill bit to maintain an air pressure or torque on the down-the-hole drill bit below a high load limit.
 9. The method for automated control of claim 6, further comprising if the down-the-hole drill bit is in the hole and the hole depth is at a desired hole depth, automatically retracting the down-the-hole drill bit. 10-15. (canceled)
 16. A method for automated control of a collaring operation of a blast hole drilling machine using a down-the-hole drill bit mounted on a drill string, comprising: automatically supplying air to the down-the-hole drill bit to provide a hammering action at the drill bit without rotating the drill bit; and automatically feeding the down-the hole drill bit to form an initial hole.
 17. The method for automated control of claim 16, further including when the initial hole is formed, automatically initiating rotation of the drill string at a rotation speed and automatically feeding the down-the-hole drill bit down the hole to drill a collar hole until a desired collaring depth is achieved.
 18. The method for automated control of claim 17, further including automatically feeding the down-the-hole drill bit down the hole at predetermined collaring increments until the desired collaring depth is achieved.
 19. (canceled)
 20. A method for automated control of a drilling operation of a blast hole drilling machine using a down-the-hole drill bit mounted on a drill string, comprising: automatically supplying air to the down-the-hole drill bit to provide a hammering action at the drill bit; and automatically controlling a feed rate of the drill string based on a measured bit air pressure during the drilling operation.
 21. The method for automated control of claim 20, further including automatically rotating the drill string based on the feed rate of the drill string.
 22. The method for automated control of claim 21, wherein the controlling of the feed rate includes maintaining the air pressure at an air pressure limit.
 23. The method for automated control of claim 22, wherein the air pressure limit is a function of drill bit characteristics.
 24. The method for automated control of claim 23, further comprising automatically controlling the feed rate of the drill string based on a feed velocity limit until the bit air pressure resulting from the drilling operation approaches the air pressure limit, and thereafter automatically controlling the feed rate based on the measured bit air pressure.
 25. The method for automated control of claim 24, wherein the automatic control of the feed rate is performed during a drill hole phase of the drilling operation.
 26. The method for automated control of claim 25, further including automatically initiating a jam avoidance operation when the bit air pressure is above a first value, but below a second value, or a measured rotation torque of the drill string is above a first torque value.
 27. The method for automated control of claim 26, wherein the jam avoidance operation includes reducing a feed rate of the drill string based on the measured bit air pressure.
 28. The method for automated control of claim 27, further including automatically initiating an anti-jam operation when the bit air pressure is above the second value or a measured rotation torque of the drill string is above a second torque value.
 29. The method for automated control of claim 28, wherein the anti-jam operation includes backing away from a jam, increasing drill rotation speed, and feeding the drill bit back into the jam at a decreased feed rate. 30-33. (canceled) 